Pneumatic hammer.



No. 66I786.` Patented Nov; 13,190.0. A. c. l-:cKwlTH: PM EumATlc HAMMER.

(Application'filed sept. 1, 1899.1

f2' Sheets-Sheet I.

hall/ XNJWQQ um Manaus mens co nnumn'lmo.; wAsmNo'roN o. c.

No. 66u86.: Patented Nav. la, |900. A. c. EcKwlTH.

PNEUMATIC HAMMER.

(Appliation led Sept. 1, 1899,) (No Model.) 2 Sheets-Sheet 2.

UNITED STATES PATENT OFFICE.

ARTHUR C. BECKVVITH, OF EAST ST. LOUIS, ILLINOIS, ASSIGNOR, BY MESNEASSIGNMENTS, TO THE WESTERN RAILWAY EQUIPMENT COMPANY, OF MISSOURI.

PNEUMATIC HAMMER.

SPECIFICATION forming` 'part of Letters Patent N o. 661,786, datedNovember 13, 1900.

Application filed September l, 1899. Serial No. 729,226. (No model.)

To atl whom it may concern: the chisel-shank will not be communicated toBe it known that I, ARTHUR C. BECKWITH, the operator. a citizen oftheUnited States, residingat the Another object is to render a tool of thiscityof East St. Louis. county of St. Clair,State character automaticwith respect to the cut- 5 `of Illinois, have invented a certain new andolf of the motive duid, so that when the en- 55 useful Improvement inPneumatic Hammers, gine is not in proper working position'it will ofwhich the following isafull,clear,and exact not idly reciprocate.description, such as will enable others skilled Another object incidentto the automatic in theart to which it appertains to make and cut-offfeature is the control or regulation lo use the same, reference beinghad to the acwith respect to the admission of the motive 6o companyingdrawings, forming part of this Huid to the engine, making the samecouispecification, in which- 'mensurate with the amount of pressure eX-Figure l is a longitudinal sectional view erted by the operator inapplying the tool to through my improved pneumatic hammer. itswork--that is, a light application of the 15 Fig. 2 is a similar viewshowing the parts in enginein its work will result in the automatic 65 adifferent position. Fig. 3 is an enlarged regulation with respect to theadmission of elevational view. Fig. 4 is a cross-sectional motive fluid,so that the piston will deliver View on line 4 4, Fig. l. Eig. 5 is across-seclight blows, while aheavy pressure in applytional View on line5 5, Fig. 2. Fig. 6 is a top ing the engine to its work will result inrenzo plan view of the cylinder or barrel, showing dering the entireinlet-port area available for 7o the piston in dotted lines in itsforward posithe admission of the greatest amount of n10- tion. 7 is abottom plan view of the cyltive fluid, so that the piston will strikeits inder or barrel, showing the piston in dotted hardest blows undersuch conditions. lines in its rearmost position. Fig. 8 is a top Withthese objects in view the invention 25 plan view of the piston. Fig. 9is a bottom consistsin the construction,arrangement,and 75 plan viewofthe piston; and Fig. 1lOis asmall combination of the several parts,all as will view of the cylinder,showing the piston therehereinafter bedescribed and afterward pointin in dotted lines, illustrating the mannerin ed out in the claims. which the chamber in front of the piston is Inthe drawings, A indicates an open-ended 3o exhausted in the forwardmovement of said sleeve carryinga suitable handle A' and pro- 80 piston.vided with a threaded nipple-opening a,- for This invention relates to anew and useful the attachment of a iiexible supply-hose for improvementin pneumatic hammers, somethe motive fluid. (Not shown.) The forwardtimes called direct-acting engines, andV is or open end of this sleevemay be provided 435 designed to be used in connection withachisel .witha series of exhaust-openings a. 85 or like tool which is loosely mountedin an 0,2 indicates an opening in the sleeve, to the opening in theforward end ornose of the cylrear of which and within the sleeve isarinder or barrel, the engine being held in the ranged aninverted-T-shaped groove ctwhose hand of an operator and guided in itsWork. purpose will hereinafter be described. 4o Motive liuid, preferablyin the form of coma indicates an opening leading from the 9o pressedair,is conducted to the engine through closed end of the sleeve to theexterior to aca iiexible hose or tube leading from some suitcommodatethe escape and admission of air able source of'supply. at atmosphericpressure behind the cylinder One object of this present invention is toor barrel to prevent the same sticking orbind- 45 construct a tool ofthe character described ing by reason of the cushioning effect of the 95with as sew parts as possible consistent with confined air at thispoint.

the results obtained. B indicates a cylinder or barrel whose for-Another object is to make a tool of this deward end or nose is formedwith a suitable scription non-vibratory-that is, the shock or openingfor the reception of a tool-shank C, 5o jar of the piston striking onthe inner end of which tool-shank is designed to entirely fill roo theopening and by so doing Iform aportion of the front wall of thecylinder. The rear end of the bore of this cylinder or barrel is formedwith a shoulder, against which is seated a cylinder-head or cap-plate D,preferably formed With an inwardly-opening chamber about its center,while the flange affords a seat for a spring E, interposed between saidcap-piece and the rear wall of the sleeve A.

F indicates a screw-bolt whose head is provided with a transverse rib f,forming a key or feather coperating with the T- shaped groove a3 insleeve A. This bolt F is introduced through the opening a2 in the sleeveand threaded into a suitable opening in the cylinder or barrel B andcarries on its inner end. a tapered projection or stud f', which ts intoa suitable recess or opening in a camroller Gr, which cooperates withthe piston. The head of bolt F prevents rotation of the cylinder in thesleeve and also arrests the forward longitudinal movement of said cylinder relative to said sleeve by abutting against the front wall ofopening a2. Bolt F therefore may be termed the locking-key between t-hecylinder and sleeve to prevent rotary motion of the cylinder within thesleeve and an excessive longitudinal motion of the cylinder relative tothesleeve, in addition to which said bolt also affords a bearing for thepiston camroller. Cylinder B is provided with an inlet-port b, com mnnicating with the opening a through a suitable groove. (See Figsl, 2,and 7.) On each side of this inletporth-are two exhaust-ports h and b2,which open into a reduced portion h3, communicating with the atmospherethrough the exhaustports ot or the opening a2 in the sleeve.

b4 is anexhaust-port,leading from the cylinder and opening into thespace h3.

H is the piston, which is preferably made solid and of uniform diameterthroughout its length, said piston operating in the bore of thecylinder, which bore is also of uniform diameter throughout its length.Piston His provided With what I will term a duplex camgroove, which isopen at the 'forward endl of said piston, but closed at its rear end. Itwill be seen by reference to Fig, 8 that the open and closed ends ofthis cam-groove are of a width substantially equal to the diameter ofthe cam-roller Grv and that said ends are circumferentially' displacedrelative to each other to the extent approximately of about forty-fivedegrees. vFora'short distance these ends of this cam-groove are formedwith parallel side walls disposed longitudinally the axis of the piston,between which points these walls are outwardly curved with relation toeach other for the purpose of giving the piston a gradual and gentleturnwhile moving in either direction, the roller G at each limit of movementof the piston in either direction coperating with the parallel walls ofthe ends ofthe groove to hold the piston approximately in a fixedrelation to the cylinder during the completion of its movement in onedirection movement.

and Afor a short period of time occupied by the piston at thecommencement of its return While the piston is free to play when theroller is in a position between the curved walls of this groove, yet inactual operation the piston only turns an amount corresponding to theiiuctuation of the cam-face with which it engages, the friction ofthemoving parts resisting independent movement of the piston. It will,however, he noted in this connection that intermediate the parallel endwalls of this cam-groove the piston 4in one movement-say forward-isrotated or displaced circumferentially an amount equal to the distancebetween the port b and either of vthe ports b' or b2, a 'reversecircumferential movement occurring on the rearward stroke of the piston.This statement is of course only true when the roller occupies aposition intermediate the ends of the groove, a greater circumferentialmovement occurring as the piston moves either forward Lor backwardbeyond a point where this roller occupies the central position abovereferred to. In the drawings I have marked the open front end of thiscam-groove h,th e rear closed end which is circumferentially displacedabout fortyiive degrees, as h', the outwardly-curved wall or cam-face,which coperates with the roller G when the piston is moving forward, ash2, and the oppositely-curved wall on the other side of the cam-groove,which cooperates with the roller G to rotate the pistou in an oppositedirection when said piston is moving rearwardly, as h3. This cam-groove,as above described, is preferably arranged on the upper half of thepiston, as shown in the drawings, While on the opposite side or lowerhalf of the piston are arranged inlet and exhaust ports which open at'opposite ends of the piston,

respectively, said ports cooperating with the inlet and exhaust ports b,b', and h2 of the cylinder'. The first of these piston-ports I willdescribe consists of a groove substantially longitudinally disposedrelativeto the axis of said piston, as-at h4, said groove being open atthe rear end of the piston, while the forward end of said groove, as atvh5, is arranged at an angle, as-shown in Fig. 9.

h6 indicates a port in advance of but communicating with the groove h5,said port being preferably formed by drilling suitable openings in thepiston.`

k7 indicates a port leading from a point to oneside of the groove h4,near-the rear end of the piston, and extending forwardly and openingthrough the front end of the piston, as shown in Fig. 9.

hs indicates a recess or port-opening communicating with the port k7,said port hs being located some distance in advance of the port-openinghrf. A

The operation of the engine'is as follows: The supply-pipe is connectedto the threaded opening ct and motive iiuid admitted to the engine. In anon-operative position spring E forces the barrel or cylinder forward,so as IOC i r l to close communication between the inletopenings a andb, so that While said cylinder is in such forward position no motivefluid can be admitted to the engine. fore, this forward longitudinalmovement of the cylinder is arrested by the bolt F, which preventsseparation of the parts. When the chisel C is introduced into the noseof the cylinder, the operator grasps the handle A with one hand while heguides the chisel in its work with the other. By pressing on the handleA the spring E is compressed and thc sleeve moves forward over thecylinder until vthe rear end of port b registers with the inlet-openinga. This opening can be coutrolled by the degree of pressure exerted onthe handle A', a slight pressure resulting in a small inlet-portopening, so that the piston will deliver light blows, while a heavierpressure insures a full inlet-port opening, admitting the greatestvolume of motive Huid to the engine, which causes the piston to deliverits heaviest blows. The motive fluid entering port b, the parts being inthe position shown in Fig. l, will pass through the port 7L? to thechamber in front of the piston, giving the piston its first impulse orinitial rearward movement. As the port h7 passes out of registrationwith the inlet-port@ the admission of motive fluid in front of thepiston is cut off and the piston travels rearwardly by the expansionthereof until the port hs registers with the inlet-port l), when thepiston receives its second impulse, the motive fluid being admitted tothe front end of the piston through port 72,8 for a short period oftime, after which, or when port hs passes out of registration with theinlet-port l), the piston is forced rearwardly by the expansion of themotive fluid in front thereof. 'lhe air behind the pistonis exhaustedthrough the groove h4 h5, which registers with the exhaustport b. (SeeFigA 4.) In the rearward movement of the piston the cam-roller Gcooperates with the curved wall h3 of the piston-groove, which causesthe registration of the channel h4 h5 with the exhaust-port b' for thegreater movement of the piston; but just before the piston reaches itsreartnost position the cam-roller rotates the piston sufficiently tocarry the channel h4 h5 out of registration with the exhaust-port b andregisters the port h with the inlet-port b, so that a sulficientquantity of motive fluid is admitted behind the piston to act asacushion and prevent the piston from striking the head D. Before thepiston reaches the limit of its rearward movement the front end thereofpasses the exhaust-opening b4, which, as shown in Fig. 6, iscomparatively large to afford aquick exhaust, and as the i'najor portionof the rearward movement of' the piston is effected under expansion ofthe two impulses heretofore described it follows that after passing thefront wall of the exhaust-opening b4 the inertia only has to beovercome, which is accomplished by lshutting off the exhaust to Asstated be-i form a cushion behind the piston and by admitting pressurebehind the piston through the port h6. (See Figs. 2 and The port h6besides admitting pressure to form the cushion described also gives :ininitial impulse to the piston in its forward movement, and when the porth6 passes out 0f registration with the inlet-port l) the piston travelsfrom the expansion of the motive iiuid first admitted until the forwardend of the chaunel h5 gets into registration with the inletport b, atand after which time the piston then travels forwardly underuninterrupted pressure,the roller G, cooperating with the curved sidewall h2 of the Vcam-groove, rotating the piston so that the inclinationof the channel h5 registers with the inlet-porto untilthe pistonapproaches the extremity of its forward movement, when the cam-grooveforces the channel h4 out of registration with the inletport. Justbefore the piston delivers its impacting blow on the tool-shank themot-ive fluid is cut off from behind the piston, and the space in frontof the piston is in communication with the atmosphere by the camgroovebeing in registration with the exhaust-port b4, (see Fig. 10,) so thatsaid space in front of the piston is being uninterruptedly exhausteduntil'the piston approaches the forward limit of its movement, when thefinal rotation of the pistou carries the cam-groove out of registrationwith the port b4. The piston now delivers its blow, compressing the airin front thereof, its final forward movement registering the port hlwith the port l), so that the rebound of the piston is utilized, inconjunction with the cushion formed and the admission of mot-ive fluidthrough the port k7, to start the piston in its rearward movement. Thiscycle of operations is repeated, the piston at the commencement of eachforward and backward movement receiving initial impulses which serve tocushion the same at the end of its stroke, after which in the forwardmovement it has au uninterrupted admission of pressure behind the saineand an uninterrupted exhaust in front thereof until approaching thecompletion of said movement, when the motive uid is cut olf. ln itsrearward movement the piston, after receiving its initialimpulse,receives a second impulse of longer duration, but for acomparatively short length of time, the major portion of the rearwardmovement of the piston resulting from the expansion of the motive fluidin front thereof derived from this second impulse, while the exhaustfrom behind the piston is uninterrupted in this movement until themovement is about completed, when said exhaust is cut olf. also be notedthat cushions are formed to prevent the piston strikingthe cylinder orbarrel at each limit of movement, which cushions are assisted by theinitial starting impulses, which may` be said to be effective before thepiston starts on its return stroke at either limit of movement, thecushions rst IOO lt will mentioned merely serving to slow down the speedof the piston preparatory to the admission of these impulses. When thechisel is removed from its work, the spring E forces the cylinderforwardly and closes communication with the inlet-ducts at and b, sothat the cessation of motion in the engine is automatic when in anon-operative position. N'ot only is this true, but the absence of thechisel from the nose of the cylinder will also prevent the engineoperating, even though the cylinder is forced rearwardly. For instance,as shown in Fig. l, if the chisel-shank were removed so as to opencommunication between the space in front of the piston and theatmosphere the motive fluid would pass through port hl and blow throughto the exf terior without forcing the piston rearwardly.

I am aware that minor changes in the arrangement, construction, andcombination of kthe several parts of my device can be made andsubstituted for those herein shown and described without in the leastdeparting from the nature and principle of myinyention.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is

l. The combination with a sleeve formed with an admission-port, ofv acylinder slidingly mounted in said sleeve and formed with an inlet-portor passage-way adapted to register With the sleeve-port` when thecylinder is in a rear position, means for exerting a pressure tending tohold the cylinder in a forward position, and a piston carried by saidcylinder; substantially as described.,

2. The combination `with a sleeve, of a longitudinally-movable cylindermounted therein, said cylinder being formed with an inletport adapted toregister with an inlet-port in the sleeve, and a spring for exertingpressure for forcing said cylinder forward to close saidinlet-ports;substantially as described.

3. In a pneumatic hammer, the combination with a sleeve, of a slidablecylinder arranged therein, a piston carried by said cylinder, and meansfor exerting constant pressure against said cylinder to hold the same ina forward position, in which forward position the supply of motive fluidis cut od from the cylinder; substantially as described.

4. In a pneumatic hammer, the combinaable cylinder mounted therein, apiston mounted in said cylinder, a chisel-shank for receiving impactingblows from said piston, and a spring interposed between the sleeve andthe rear end of `the cylinder for rendering the machine inoperative whenin normal position; substantially as described.

6. In a pneumatic hammer, the combination with a sleeve or support, of acylinder mounted therein and adapted to move longitudinally thereof, apiston arranged in said cylinder, a chisel-shank mounted in the forwardend of said-cylinder, and means exerting a constant pressure to holdsaid cylinder.

in'a forward position to cut off the supply of motive iiuid therefrom;substantially as described.

.7. In a pneumatic hammer, the combination with a sleeve or othersupport, of a longitudinally-movable cylinder mounted there-.

shank forming a portion of the front end wall of the cylinder;substantially as described.

9. In a pneumatic hammer, the combination with a sleeve, of alongitudinally-movable cylinder mounted therein,.alongitudinally-movable head for closing the rear end of the cylinder,and a yielding medium interposed between the sleeve and the cylinderheadfor yieldingly holding the latter in position; substantiallyasdescribed.

10. The combination with a sleeve, of alongitudinally-movable cylindermounted therein, a piston mounted in said cylinder, a bolt mounted insaid cylinder for limiting its longitudinal movement and 'preventingrotation thereof; substantially as described.

ll. The combination with a sleeve, of a longitudinally-movable cylindermountedxtherein, a bolt mounted in said cylinder for limiting itslongitudinal movement and preventing rotation thereof vrelative to thesleeve, a

IOO

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. A. l "l operator in order that the pressure may beincreased againstthe cylinder by compressing said spring when the sleeve is slid forwardover the cylinder; substantially as described.

5. In a pneumatic hammer, the combination with a sleeve, of alongitudinally-movpiston mounted in the cylinder and provided with aspiral groove, and a roller mounted on i the end of said bolt andfitting in said groove;

substantially as described.

12. The combination with asleeve provided with an opening a2, and arecessed portion a3 yadjacent to said opening, a longitudinallymovablecylinder mounted in said sleeve, and a bolt "which is introduced into asuitable opening in said cylinder through the opening a2, the head ofsaid bolt being received by the recess a3, when the cylinder is movedlongitudinally in the sleeve; substantially as described.

13. The combination with `a cylinder, of a bolt formed with a tapered'stud on its inner end projecting Within the cylinder, a roller looselymounted on said tapered stud, and a piston formed with a spiral groovefor coperating with said roller, said piston being also formed withports coperating with cylinderports, whereby when said piston is at orabout the extremity of either movement it receives an impulse ofcomparatively short duration, substantially as described.

14. The combination with a cylinder provided with an inlet-port, and apiston formed with a plurality of ports cooperating with thecylinder-port in such manner that, in its forward movement, the pistonreceives an initial impulse and then an uninterrupted supply of rearwardmovement, receives pressure in front thereof, in the form of impulses,said cylinder and piston being provided with cooperating ports whereby,when the piston is moving rearwardly, the pressure therebehind isexhausted uniuterfuptedly; 'substantially as described.

16. A pneumatic hammer comprising a cyl- -inder having a bearing for atool at one end and provided with' an inlet-port and exhaustports oneach side of said inlet-port, and a piston iitted to slide andturn inthe cylinder, said piston being provided with blind passages h, k7, andhs, and an open passage h, h5; substantially as described.

17. A pneumatic hammer comprising a cyl'- piston being also providedwitha spiral.

groove, and a roller carried by the cylinder and working in the saidspiral groove; substantially as described.

18. A pneumatic hammer comprising a cylinder having a bearing for a toolat one end and provided with an inlet-port and exhaustports on each sideof said inlet-port, a piston fitted to slide and turn in the cylinder,said piston being provided with blind passages h6, h7, and hs, and anopen passage h4, h5, the piston being also provided with a spiral grooveopen at one end thereof, oppositely-curved walls of said groovesintermediate the ends cooperating with a fixed roller to partiallyrotate said piston at dierent points in its forward and backwardmovements, and a stationary roller mounted in the cylinder forcooperating With said piston-groove; substantially as described.

` 19. In a pneumatic hammer, the combination with a sleeve or othersupport, of a cylinderlongtudinally movable therein, apiston carried bysaid cylinder, a chisel forming a portion of the front end wall of thecylinder, and a spring-pressed movable cap piece or head forming therear Wall of said cylinder; substantially as described.

In testimony whereof I hereunto ax my signature, in the presence of twowitnesses, this 29th day of August, 1899.

ARTHUR C. BECKWITH.

Witnesses:

F. R. CORNWALL,

A. S. GRAY.

